Psychometric properties of the Quick Inventory of Depressive Symptomatology in adolescents

Objective: The clinician‐rated (QIDS‐C₁₆) and self‐report (QIDS‐SR₁₆) versions of the 16‐item Quick Inventory of Depressive Symptomatology have been extensively examined in adult populations. This study evaluated both versions of the QIDS and the 17‐item Children's Depressive Rating Scale – Revised (CDRS‐R) in an adolescent outpatient sample. Method: Both the QIDS‐C₁₆ and QIDS‐SR₁₆ were completed for the adolescents. Three different methods were used to complete the QIDS‐C₁₆: (a) adolescents' responses to clinician interviews; (b) parents' responses to clinician interview; and (c) a composite score using the most pathological response from the two interviews. Both classical and item response theory methods were used. Factor analyses evaluated the dimensionality of each scale. Results: The sample included 140 adolescent outpatients. All versions of the QIDS, save the parent interview, and the CDRS‐R were very reliable (α ≥ 0.8). All four versions of the QIDS are reasonably effective and unidimensional. The CDRS‐R was clearly at least two‐dimensional. The CDRS‐R was the most discriminating among low and extremely high levels of depression. The QIDS‐SR₁₆ was the most discriminating at moderate levels of depression. There was no relation between the QIDS scores and concurrent Axis III comorbidities. Conclusion: The QIDS‐C₁₆ and the QIDS‐SR₁₆ are suitable for use in adolescents. Copyright © 2010 John Wiley & Sons, Ltd.